Balanced valve



(No Model.)

P. ARMINGTON.

BALANCED VALVE.

No. 244,161. Patented July 12, 18811.

I IIIIII UNITED STATES PATENT OFFI' PARDON ARMINGTON, OF LAWRENCE, MASSACHUSETTS.

BALANCED VALVE.

SPECIFICATION forming part of Letters Patent No. 244,161, dated July 12, 1881. Application filed April 6, 1881. (No model.)

To all whom it may concern:

Be it known that I, PARDON ARMINGTON, of Lawrence, county of Essex, State of Massachusetts, have invented an Improvement in Balanced Valves for Steam-Engines, of which the following description, in connection with the accompanying drawings,is a specification.

My invention relating to valves is shown embodied in a balanced valve; and has for its object, among other things, to maintain the port-opening for steam asnearly constant as possible during the entire period that steam is being admitted to the cylinder.

In engines using slide-valves as commonly constructed and operated by an eccentric the valve in its movement gradually uncovers the port-opening, making a gradually-increasing passage for the steam measured from one edge of the port-opening in the valve-seat to the edge of the valve moving over the said opening, and after the opening has been entirely opened the valve travels in the other direction and gradually closes the port.

My invention is embodied in a valve and valve-seat provided with such passages that steam is admitted at both edges of the port leading to the cylinder simultaneously, and the maximum opening is thus attained when the edge of the valve has traveled only a short distance beyond the edge of the portopening, about equal amounts of steam being then admitted at both edges of the said port-opening, and in the further travel of the valve the uncovered space at one edge of the port-opening is increased, while that of the other edge is decreased by the same amount, so that the total openingremains about constant. In closing the valve the reverse operation takes place, so that with a small movement of the valve the space for admission of steam will be sad denly increased to a maximum and then maintained there during the further movement, until just at the end of the return movement the port is suddenly closed and thesupply of steam cut oil.

The invention. consists, partly, in the combination, with a port having two openings in the valve-seat, of a valve adapted to admit the steam at both edges of each opening.

The invention also consists in a novel construction of the packing-ring, by which the valve is relieved from steam-pressure, the said packing-ring resting on a plane seat on the upper portion or back of the valve, and being tightly fitted in a cylinder in the cover of the steam-chest, as is usual in this class of balancing-valves, a chamber thus being formed above the valve, from which steam is excluded. I construct the said ring so that a larger area is inclosed by it upon the back of the valve than the area occupied by the said packingring in the cover of the steam-chest, so that there is an unbalanced steam-pressure due to the difference of these areas acting to press the ring to its seat upon the valve. I also employ a spring to insure the proper seating of the ring before steam is admitted to the steam-chest. I have observed that balancingrings of this class, as usually constructed, do not properly exclude the steam from the spaces or chamber above the valve, probably owing to the fact that a thin film of steam enters between the said valve and ring, supporting the said ring, and flowing in to fill the chamber, which thus fails to relieve the valve of steampressure. I have succeeded in overcoming this difficulty by providing the undervface of the pa'ckin g-rin g with an annular channel passing around near its outer edge and connected with the interior of the chamber above the valve, from which the steam is tobe excluded. By this arrangement, if a film of steam should pass beneath the packing-rin g, it would, on arriving at this annular passage, at once find a free course to the interior ofthe said chamber, thus at once reducing the pressure between the bearing-portion of the valve and ring, and allowing the ring to come to its seat,

since the area on which the film of steam can v act with full pressure is made less than the area acted upon by the steam in the chest to Force the ring to its seat. A small passageis provided, leading from the chamber above the valve to the outside of the steam-chest, so that the water of condensation can be removed from the said chamber, and this passageis provided with a pet-cock to enable the condition of the chamberat any time to be tested. If this cock, when opened, shows a steam-pressure in the chamber, it will indicate that the steam is not properly excluded therefrom, and, should steam I continue to pass out, it would show the packing-ring was leaking at some point.

Figure 1 is a longitudinal section of a portion of a steam-chest and valve therein constructed in accordance with my invention, the said valve being closed; Fig. 2, a section of a portion of the valve and its seat, the valve having arrived at such a position as to give the maximum opening; Fig. 3, an under-side view of the balancing packing-rim g.

The cylinder at and steanrehest b may be constructed in any usual manner, the said cylinder being shown as provided with a port, 0, provided with a main passage, 0', and a branch passage, 67, leading to openings in the valve-seat 0, controlled by the valve j, which is shown as intended to govern only the admission of steam to one end of the cylinder a. The openings in the valve-seat are shown as enlarged to about double the sectional area of the said passages, so that when they are about one-half uncovered they will afford a free passage to as large an amount of steam as will pass freely through the said passages into the cylinder. The valve f has a passage, g, connecting with the steamchest, and is thus divided into what forms, essentially, two valves, one controlling the main passage 0, and the other the branch-passage d, the valve thus divided enabling a certain amount of movement to produce double the cffeet that would be produced by a single valve, and thus operating on the principle of the wellknown grid-iron valve. The valve-seat e is depressed or cut away, as shown at 2, the said depression being in communication with the steam-chest or with the passage 9 in the valve, and thus forming in reality two valve-seats, one for the port a and the other for the port 01.

Referring to the portion of the valve-seat containin g the opening to the main passage 0 and that portion of the valve controlling it, the said valve has a chamber, It, made in its face, of a width about equal to the opening of the port 0, the said chamber h not communicating with the steam-chest while it is above the elevated portion of the valve-seat e or the said opening to the port, but brought into connection with the said steam-chest as soon as it has passed over the elevated portion of the valve-seat 0.

When in the movement of the valve in the direction of the arrow thereon its edge 3 arrives at the edge 4 of the port-opening, and begins to uncover the said opening, the edge 5 of the chamber It will arrive at the edge of the depression 2 in the valve-seat, thus allowing steam to pass from the said depression through the said chamber h into the port-openin g, which is at this time about one-half overlappedby the said chamber h. As the valve continues to move the opening between the edges 3 and 4:, and at the edge 5 of the passage h, bothincrease together, so that the total amount of opening will be double that which would be produced if the face of the valve were not provided with the said chamber and the only opening was that between the edges 3 and 4, and consequently the maximum amount of opening will be attained in one-half the time that would be necessary with an ordinary valve. After this maximum is attained, and the valve continues to travel in the same direction, as shown in Fig. 2, the opening between the edges 3 and 4 will increase, while that between the edge 6 of the chamber h and that of the port-opening will decrease, so that the total opening will remain constant until the said edge 6 has reached the edge of the port, when the said port will be practically wholly uncovered, and on the further movement of the valve in this direction the full amount of steam will continue to flow into the cylinder. When the valve moves in the reverse direction its edge 3 will not begin to diminish the volume of steam until it gets in line with the edge of the contracted portion of the port below its opening in the valve-seat, and at this moment the edge 6 of the chamber h will have reached the edge of the uncontracted portion of the said opening, so that in the further movement the opening at6 will increase, while that between the edges 3 and 4 decreases, and the total amount of opening will thus remain constant until in the' last part of the movement the edges 3 and 5, acting simultaneously, rapidly cut ofl the steam, and wholly close the port in the further movement of the valve.

The opening h in that portion of the valve controlling the branch passage d to the cylinder operates in precisely similar manner, the flow of steam to the cylinder being indicated in Fig. 2 by the arrows.

The space on the face of the valve, between the edge 3 and the edge 6 of the chamber h, should be about equal to the enlargement of the port-opening above the sectional area of the port.

The upper portion, "6, of the valve is made plane, to form a tight seat for the packing or balancing ring j, fitted tightly in a short cylindrical projection, 70, from the inside of the steam-chest cover, in which it is tightly packed in any suitable manner, as by the metallic ring 1, held in place by the follower-ring-m, bolted upon the said packing-ringj. The area inclosed by the packing-ring j upon the seat portion t of the valve f is greater than the internal sectional area of the cylinder 70, so that an annular portion of the said ring is exposed to an unbalanced downward pressure upon the seat portion t of the valve.

A spring, a, interposed between the central or hub portion, 0, of the ring j, and a cap, p, bolted upon the steam-chest cover, also tends to press the ring j down upon the valve, thus holding it securely to its seatbefore steam-is admitted to the chest I).

The bearing-face of the ring j is provided with an annular channel, 1', (see Fig. 3, near its outer edge,) the said channel being connected by passages s with the spaces inclosed within the ring 7' and cylinder 70, between the valve and steam-chest cover, from which it is intended to exclude the steam to relieve the valve of its pressure. By this construction of the ring, should it at any time happen to be imperfectly seated when steam was let into the chest, the film of steam passing between the face of the ring and the seat portion 13 of the valve and exerting an upward pressure on the said ring would, on arriving at the channel 4", have free access to the interior of the ring, so that the only portion acted upon by this film to prevent the ring from seating would be the narrow annular area t, (see Fig. 3,) much less than the annular area acted upon by the downward pressure of the steam in the chest, and consequently the ring would at once he brought to its seat, the film of steam beneath it being overpowered and excluded.

A passage, to, (shown in dotted lines, Fig. 1,) leads from the interior of the cylinder 76 outside the steam-chest, where it is preferably controlled by a pet-cock, this passage serving to draw off water of condensation from within the cylinder k, and also indicating whether the steam is properly excluded from the said cylinder or not.

It is obvious that the cylinder it might be on the back of the valve, and the ring j have its 7 seat on the cover of the steam-chest, without departing from my'invention but I prefer the construction hereinbefore described.

I claim- 1. The valve-seat, and main and branch port openings therein, and depression 2 between them, combined with the valve provided with a central passage communicating with the steamchest, and with chambers h h to provide a passage from the steam-chest to the ports in certain positions of the valve, substantially as described.

2. The valve and its seat portion, and the packing-ring resting thereon, provided with an annular channel, 1", in its bearing-face and passages 3 connecting the said channel with the interior of the ring,- combined with the steamchest cover, and cylinder therein to receive the said ring, substantially as described.

In testimony whereof I have signed my name 5 to this specification in the presence of two subscribing witnesses.

PARDON ARMINGTON.

' Witnesses:

DANIEL NASON, E. A. FIsKE. 

